The proliferative response of vascular smooth muscle cells (VSMCs) plays a key role in the recovery of arteries from injury and the development of cardiovascular diseases. The broad long-term objective of this research is to understand pathways important for transmission of proliferative signals from the cytoplasm to the nuclear transcription machinery in VSMCs. A relationship between Ca2+ and proliferation has been implicated, but the mechanisms have not been identified. In addition, whereas transmission of Ca2+ and mitogenic signals is necessary to elicit specific changes in gene expression, the communication between these pathways in the cytoplasm and nucleus is not known. The specific aims of this proposal explore a novel mechanism for Ca2+-mediated gene transcription in smooth muscle in which distinct sources of Ca2+ interact with extracellular signal-regulated kinase (ERK) signals to elicit specific transcriptional programs that are necessary for the development of hypertension-induced pathologies. Previous studies by this laboratory group have shown that different sources of Ca2+ lead to the activation of the Ca2+/cAMP response element binding protein (CREB) resulting in transcription of selective gene targets. The specific aims of this proposal explore the molecular mechanisms of these findings by 1) Exploring the connection between specific Ca2+ signals and kinase activation that determine selective gene expression in VSMCs;2) Identifying factors that interact with CRE-containing promoters in response to Ca2+ signals;and 3) Defining a role for CREB and ERK signaling in gene transcription that modulates hypertension-induced proliferation and migration of VSMCs. To achieve these aims, the proposed experiments will use live-cell Ca2+ imaging, kinase assays, immunologic assays, chromatin analysis, promoter/transcription analysis, cell and intact artery transfection, and an in vivo model of hypertension. The research personnel have expertise in cell signaling, vascular biology, and Ca2+ dynamics. The integrated experimental design, which combines cultured cell and intact artery approaches, will drive support for new paradigms in Ca2+-regulated gene transcription and the results of these experiments have the potential to identify new targets for reducing vascular pathologies associated with VSMC proliferation.